1 /*
2  * Marvell Armada 370 and Armada XP SoC IRQ handling
3  *
4  * Copyright (C) 2012 Marvell
5  *
6  * Lior Amsalem <alior@marvell.com>
7  * Gregory CLEMENT <gregory.clement@free-electrons.com>
8  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
9  * Ben Dooks <ben.dooks@codethink.co.uk>
10  *
11  * This file is licensed under the terms of the GNU General Public
12  * License version 2.  This program is licensed "as is" without any
13  * warranty of any kind, whether express or implied.
14  */
15 
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/irq.h>
20 #include <linux/interrupt.h>
21 #include <linux/io.h>
22 #include <linux/of_address.h>
23 #include <linux/of_irq.h>
24 #include <linux/of_pci.h>
25 #include <linux/irqdomain.h>
26 #include <linux/slab.h>
27 #include <linux/msi.h>
28 #include <asm/mach/arch.h>
29 #include <asm/exception.h>
30 #include <asm/smp_plat.h>
31 #include <asm/mach/irq.h>
32 
33 #include "irqchip.h"
34 
35 /* Interrupt Controller Registers Map */
36 #define ARMADA_370_XP_INT_SET_MASK_OFFS		(0x48)
37 #define ARMADA_370_XP_INT_CLEAR_MASK_OFFS	(0x4C)
38 
39 #define ARMADA_370_XP_INT_CONTROL		(0x00)
40 #define ARMADA_370_XP_INT_SET_ENABLE_OFFS	(0x30)
41 #define ARMADA_370_XP_INT_CLEAR_ENABLE_OFFS	(0x34)
42 #define ARMADA_370_XP_INT_SOURCE_CTL(irq)	(0x100 + irq*4)
43 
44 #define ARMADA_370_XP_CPU_INTACK_OFFS		(0x44)
45 
46 #define ARMADA_370_XP_SW_TRIG_INT_OFFS           (0x4)
47 #define ARMADA_370_XP_IN_DRBEL_MSK_OFFS          (0xc)
48 #define ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS        (0x8)
49 
50 #define ARMADA_370_XP_MAX_PER_CPU_IRQS		(28)
51 
52 #define ARMADA_370_XP_TIMER0_PER_CPU_IRQ	(5)
53 
54 #define IPI_DOORBELL_START                      (0)
55 #define IPI_DOORBELL_END                        (8)
56 #define IPI_DOORBELL_MASK                       0xFF
57 #define PCI_MSI_DOORBELL_START                  (16)
58 #define PCI_MSI_DOORBELL_NR                     (16)
59 #define PCI_MSI_DOORBELL_END                    (32)
60 #define PCI_MSI_DOORBELL_MASK                   0xFFFF0000
61 
62 static DEFINE_RAW_SPINLOCK(irq_controller_lock);
63 
64 static void __iomem *per_cpu_int_base;
65 static void __iomem *main_int_base;
66 static struct irq_domain *armada_370_xp_mpic_domain;
67 #ifdef CONFIG_PCI_MSI
68 static struct irq_domain *armada_370_xp_msi_domain;
69 static DECLARE_BITMAP(msi_used, PCI_MSI_DOORBELL_NR);
70 static DEFINE_MUTEX(msi_used_lock);
71 static phys_addr_t msi_doorbell_addr;
72 #endif
73 
74 /*
75  * In SMP mode:
76  * For shared global interrupts, mask/unmask global enable bit
77  * For CPU interrupts, mask/unmask the calling CPU's bit
78  */
79 static void armada_370_xp_irq_mask(struct irq_data *d)
80 {
81 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
82 
83 	if (hwirq != ARMADA_370_XP_TIMER0_PER_CPU_IRQ)
84 		writel(hwirq, main_int_base +
85 				ARMADA_370_XP_INT_CLEAR_ENABLE_OFFS);
86 	else
87 		writel(hwirq, per_cpu_int_base +
88 				ARMADA_370_XP_INT_SET_MASK_OFFS);
89 }
90 
91 static void armada_370_xp_irq_unmask(struct irq_data *d)
92 {
93 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
94 
95 	if (hwirq != ARMADA_370_XP_TIMER0_PER_CPU_IRQ)
96 		writel(hwirq, main_int_base +
97 				ARMADA_370_XP_INT_SET_ENABLE_OFFS);
98 	else
99 		writel(hwirq, per_cpu_int_base +
100 				ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
101 }
102 
103 #ifdef CONFIG_PCI_MSI
104 
105 static int armada_370_xp_alloc_msi(void)
106 {
107 	int hwirq;
108 
109 	mutex_lock(&msi_used_lock);
110 	hwirq = find_first_zero_bit(&msi_used, PCI_MSI_DOORBELL_NR);
111 	if (hwirq >= PCI_MSI_DOORBELL_NR)
112 		hwirq = -ENOSPC;
113 	else
114 		set_bit(hwirq, msi_used);
115 	mutex_unlock(&msi_used_lock);
116 
117 	return hwirq;
118 }
119 
120 static void armada_370_xp_free_msi(int hwirq)
121 {
122 	mutex_lock(&msi_used_lock);
123 	if (!test_bit(hwirq, msi_used))
124 		pr_err("trying to free unused MSI#%d\n", hwirq);
125 	else
126 		clear_bit(hwirq, msi_used);
127 	mutex_unlock(&msi_used_lock);
128 }
129 
130 static int armada_370_xp_setup_msi_irq(struct msi_chip *chip,
131 				       struct pci_dev *pdev,
132 				       struct msi_desc *desc)
133 {
134 	struct msi_msg msg;
135 	irq_hw_number_t hwirq;
136 	int virq;
137 
138 	hwirq = armada_370_xp_alloc_msi();
139 	if (hwirq < 0)
140 		return hwirq;
141 
142 	virq = irq_create_mapping(armada_370_xp_msi_domain, hwirq);
143 	if (!virq) {
144 		armada_370_xp_free_msi(hwirq);
145 		return -EINVAL;
146 	}
147 
148 	irq_set_msi_desc(virq, desc);
149 
150 	msg.address_lo = msi_doorbell_addr;
151 	msg.address_hi = 0;
152 	msg.data = 0xf00 | (hwirq + 16);
153 
154 	write_msi_msg(virq, &msg);
155 	return 0;
156 }
157 
158 static void armada_370_xp_teardown_msi_irq(struct msi_chip *chip,
159 					   unsigned int irq)
160 {
161 	struct irq_data *d = irq_get_irq_data(irq);
162 	irq_dispose_mapping(irq);
163 	armada_370_xp_free_msi(d->hwirq);
164 }
165 
166 static struct irq_chip armada_370_xp_msi_irq_chip = {
167 	.name = "armada_370_xp_msi_irq",
168 	.irq_enable = unmask_msi_irq,
169 	.irq_disable = mask_msi_irq,
170 	.irq_mask = mask_msi_irq,
171 	.irq_unmask = unmask_msi_irq,
172 };
173 
174 static int armada_370_xp_msi_map(struct irq_domain *domain, unsigned int virq,
175 				 irq_hw_number_t hw)
176 {
177 	irq_set_chip_and_handler(virq, &armada_370_xp_msi_irq_chip,
178 				 handle_simple_irq);
179 	set_irq_flags(virq, IRQF_VALID);
180 
181 	return 0;
182 }
183 
184 static const struct irq_domain_ops armada_370_xp_msi_irq_ops = {
185 	.map = armada_370_xp_msi_map,
186 };
187 
188 static int armada_370_xp_msi_init(struct device_node *node,
189 				  phys_addr_t main_int_phys_base)
190 {
191 	struct msi_chip *msi_chip;
192 	u32 reg;
193 	int ret;
194 
195 	msi_doorbell_addr = main_int_phys_base +
196 		ARMADA_370_XP_SW_TRIG_INT_OFFS;
197 
198 	msi_chip = kzalloc(sizeof(*msi_chip), GFP_KERNEL);
199 	if (!msi_chip)
200 		return -ENOMEM;
201 
202 	msi_chip->setup_irq = armada_370_xp_setup_msi_irq;
203 	msi_chip->teardown_irq = armada_370_xp_teardown_msi_irq;
204 	msi_chip->of_node = node;
205 
206 	armada_370_xp_msi_domain =
207 		irq_domain_add_linear(NULL, PCI_MSI_DOORBELL_NR,
208 				      &armada_370_xp_msi_irq_ops,
209 				      NULL);
210 	if (!armada_370_xp_msi_domain) {
211 		kfree(msi_chip);
212 		return -ENOMEM;
213 	}
214 
215 	ret = of_pci_msi_chip_add(msi_chip);
216 	if (ret < 0) {
217 		irq_domain_remove(armada_370_xp_msi_domain);
218 		kfree(msi_chip);
219 		return ret;
220 	}
221 
222 	reg = readl(per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS)
223 		| PCI_MSI_DOORBELL_MASK;
224 
225 	writel(reg, per_cpu_int_base +
226 	       ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
227 
228 	/* Unmask IPI interrupt */
229 	writel(1, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
230 
231 	return 0;
232 }
233 #else
234 static inline int armada_370_xp_msi_init(struct device_node *node,
235 					 phys_addr_t main_int_phys_base)
236 {
237 	return 0;
238 }
239 #endif
240 
241 #ifdef CONFIG_SMP
242 static int armada_xp_set_affinity(struct irq_data *d,
243 				  const struct cpumask *mask_val, bool force)
244 {
245 	unsigned long reg;
246 	unsigned long new_mask = 0;
247 	unsigned long online_mask = 0;
248 	unsigned long count = 0;
249 	irq_hw_number_t hwirq = irqd_to_hwirq(d);
250 	int cpu;
251 
252 	for_each_cpu(cpu, mask_val) {
253 		new_mask |= 1 << cpu_logical_map(cpu);
254 		count++;
255 	}
256 
257 	/*
258 	 * Forbid mutlicore interrupt affinity
259 	 * This is required since the MPIC HW doesn't limit
260 	 * several CPUs from acknowledging the same interrupt.
261 	 */
262 	if (count > 1)
263 		return -EINVAL;
264 
265 	for_each_cpu(cpu, cpu_online_mask)
266 		online_mask |= 1 << cpu_logical_map(cpu);
267 
268 	raw_spin_lock(&irq_controller_lock);
269 
270 	reg = readl(main_int_base + ARMADA_370_XP_INT_SOURCE_CTL(hwirq));
271 	reg = (reg & (~online_mask)) | new_mask;
272 	writel(reg, main_int_base + ARMADA_370_XP_INT_SOURCE_CTL(hwirq));
273 
274 	raw_spin_unlock(&irq_controller_lock);
275 
276 	return 0;
277 }
278 #endif
279 
280 static struct irq_chip armada_370_xp_irq_chip = {
281 	.name		= "armada_370_xp_irq",
282 	.irq_mask       = armada_370_xp_irq_mask,
283 	.irq_mask_ack   = armada_370_xp_irq_mask,
284 	.irq_unmask     = armada_370_xp_irq_unmask,
285 #ifdef CONFIG_SMP
286 	.irq_set_affinity = armada_xp_set_affinity,
287 #endif
288 };
289 
290 static int armada_370_xp_mpic_irq_map(struct irq_domain *h,
291 				      unsigned int virq, irq_hw_number_t hw)
292 {
293 	armada_370_xp_irq_mask(irq_get_irq_data(virq));
294 	if (hw != ARMADA_370_XP_TIMER0_PER_CPU_IRQ)
295 		writel(hw, per_cpu_int_base +
296 			ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
297 	else
298 		writel(hw, main_int_base + ARMADA_370_XP_INT_SET_ENABLE_OFFS);
299 	irq_set_status_flags(virq, IRQ_LEVEL);
300 
301 	if (hw == ARMADA_370_XP_TIMER0_PER_CPU_IRQ) {
302 		irq_set_percpu_devid(virq);
303 		irq_set_chip_and_handler(virq, &armada_370_xp_irq_chip,
304 					handle_percpu_devid_irq);
305 
306 	} else {
307 		irq_set_chip_and_handler(virq, &armada_370_xp_irq_chip,
308 					handle_level_irq);
309 	}
310 	set_irq_flags(virq, IRQF_VALID | IRQF_PROBE);
311 
312 	return 0;
313 }
314 
315 #ifdef CONFIG_SMP
316 void armada_mpic_send_doorbell(const struct cpumask *mask, unsigned int irq)
317 {
318 	int cpu;
319 	unsigned long map = 0;
320 
321 	/* Convert our logical CPU mask into a physical one. */
322 	for_each_cpu(cpu, mask)
323 		map |= 1 << cpu_logical_map(cpu);
324 
325 	/*
326 	 * Ensure that stores to Normal memory are visible to the
327 	 * other CPUs before issuing the IPI.
328 	 */
329 	dsb();
330 
331 	/* submit softirq */
332 	writel((map << 8) | irq, main_int_base +
333 		ARMADA_370_XP_SW_TRIG_INT_OFFS);
334 }
335 
336 void armada_xp_mpic_smp_cpu_init(void)
337 {
338 	/* Clear pending IPIs */
339 	writel(0, per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
340 
341 	/* Enable first 8 IPIs */
342 	writel(IPI_DOORBELL_MASK, per_cpu_int_base +
343 		ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
344 
345 	/* Unmask IPI interrupt */
346 	writel(0, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
347 }
348 #endif /* CONFIG_SMP */
349 
350 static struct irq_domain_ops armada_370_xp_mpic_irq_ops = {
351 	.map = armada_370_xp_mpic_irq_map,
352 	.xlate = irq_domain_xlate_onecell,
353 };
354 
355 static asmlinkage void __exception_irq_entry
356 armada_370_xp_handle_irq(struct pt_regs *regs)
357 {
358 	u32 irqstat, irqnr;
359 
360 	do {
361 		irqstat = readl_relaxed(per_cpu_int_base +
362 					ARMADA_370_XP_CPU_INTACK_OFFS);
363 		irqnr = irqstat & 0x3FF;
364 
365 		if (irqnr > 1022)
366 			break;
367 
368 		if (irqnr > 1) {
369 			irqnr =	irq_find_mapping(armada_370_xp_mpic_domain,
370 					irqnr);
371 			handle_IRQ(irqnr, regs);
372 			continue;
373 		}
374 
375 #ifdef CONFIG_PCI_MSI
376 		/* MSI handling */
377 		if (irqnr == 1) {
378 			u32 msimask, msinr;
379 
380 			msimask = readl_relaxed(per_cpu_int_base +
381 						ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS)
382 				& PCI_MSI_DOORBELL_MASK;
383 
384 			writel(~PCI_MSI_DOORBELL_MASK, per_cpu_int_base +
385 			       ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
386 
387 			for (msinr = PCI_MSI_DOORBELL_START;
388 			     msinr < PCI_MSI_DOORBELL_END; msinr++) {
389 				int irq;
390 
391 				if (!(msimask & BIT(msinr)))
392 					continue;
393 
394 				irq = irq_find_mapping(armada_370_xp_msi_domain,
395 						       msinr - 16);
396 				handle_IRQ(irq, regs);
397 			}
398 		}
399 #endif
400 
401 #ifdef CONFIG_SMP
402 		/* IPI Handling */
403 		if (irqnr == 0) {
404 			u32 ipimask, ipinr;
405 
406 			ipimask = readl_relaxed(per_cpu_int_base +
407 						ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS)
408 				& IPI_DOORBELL_MASK;
409 
410 			writel(~IPI_DOORBELL_MASK, per_cpu_int_base +
411 				ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
412 
413 			/* Handle all pending doorbells */
414 			for (ipinr = IPI_DOORBELL_START;
415 			     ipinr < IPI_DOORBELL_END; ipinr++) {
416 				if (ipimask & (0x1 << ipinr))
417 					handle_IPI(ipinr, regs);
418 			}
419 			continue;
420 		}
421 #endif
422 
423 	} while (1);
424 }
425 
426 static int __init armada_370_xp_mpic_of_init(struct device_node *node,
427 					     struct device_node *parent)
428 {
429 	struct resource main_int_res, per_cpu_int_res;
430 	u32 control;
431 
432 	BUG_ON(of_address_to_resource(node, 0, &main_int_res));
433 	BUG_ON(of_address_to_resource(node, 1, &per_cpu_int_res));
434 
435 	BUG_ON(!request_mem_region(main_int_res.start,
436 				   resource_size(&main_int_res),
437 				   node->full_name));
438 	BUG_ON(!request_mem_region(per_cpu_int_res.start,
439 				   resource_size(&per_cpu_int_res),
440 				   node->full_name));
441 
442 	main_int_base = ioremap(main_int_res.start,
443 				resource_size(&main_int_res));
444 	BUG_ON(!main_int_base);
445 
446 	per_cpu_int_base = ioremap(per_cpu_int_res.start,
447 				   resource_size(&per_cpu_int_res));
448 	BUG_ON(!per_cpu_int_base);
449 
450 	control = readl(main_int_base + ARMADA_370_XP_INT_CONTROL);
451 
452 	armada_370_xp_mpic_domain =
453 		irq_domain_add_linear(node, (control >> 2) & 0x3ff,
454 				&armada_370_xp_mpic_irq_ops, NULL);
455 
456 	BUG_ON(!armada_370_xp_mpic_domain);
457 
458 	irq_set_default_host(armada_370_xp_mpic_domain);
459 
460 #ifdef CONFIG_SMP
461 	armada_xp_mpic_smp_cpu_init();
462 
463 	/*
464 	 * Set the default affinity from all CPUs to the boot cpu.
465 	 * This is required since the MPIC doesn't limit several CPUs
466 	 * from acknowledging the same interrupt.
467 	 */
468 	cpumask_clear(irq_default_affinity);
469 	cpumask_set_cpu(smp_processor_id(), irq_default_affinity);
470 
471 #endif
472 
473 	armada_370_xp_msi_init(node, main_int_res.start);
474 
475 	set_handle_irq(armada_370_xp_handle_irq);
476 
477 	return 0;
478 }
479 
480 IRQCHIP_DECLARE(armada_370_xp_mpic, "marvell,mpic", armada_370_xp_mpic_of_init);
481